text: The metric tensor  is sometimes used for calculations involving the unit cell and is defined (in matrix form) as:
  In two dimensions,
  In three dimensions,
  The distance between two points  and  in the unit cell can be determined from the relation:
  The distance from the origin of the unit cell to a point  within the unit cell can be determined from the relation:
  The angle formed from three points ,  (apex), and  within the unit cell can determined from the relation:
  The volume of the unit cell,  can be determined from the relation: